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Unformatted text preview: tualistic. B) competitive. D) commensal. 37) Legumes, such as beans or peas form A) mutualist associations with nitrogen‐fixing bacteria. B) mycorrhizal associations to increase fixation. C) parasitic relationships with other plants. D) N2 from the atmosphere in their leaves. 38) Carnivorous plants are more likely to grow in acid bogs because A) organic matter decays so slowly there. B) acid soil inhibits growth of plant roots. C) acid rain damages leaves and stems. D) mycorrhizal growth is inhibited. 39) An organism that parasitizes a host plant is A) mycorrhizal fungus. C) a Venus flytrap. B) nitrogen bacteria. D) mistletoe. 40) Which of the following is most likely an epiphyte? A) a plant growing on the branches of another plant B) a plant that captures insects C) a plant with a very deep root system D) a plant that parasitizes another plant 41) Plants grow toward light through the action of A) hormones. C) solar energy. B) nerves. D) chloroplasts 42) Grass shoots bend toward the light because, on the shadowed side, a(n) A) reduction in auxin levels promotes cell elongation. B) reduction in auxin levels prevents cell elongation. C) increase in auxin levels promotes cell elongation. D) increase in auxin levels promotes cell division. 43) An experiment in phototropism involved cutting grass seedling tips before exposing them to light from one side. Decapitated seedlings did not bend toward light. A valid conclusion from this would be that A) plants cannot engage in photosynthesis without the tip. B) light is perceived by the tip of grass plants. C) a foil cover over the tip would cause them to bend. D) hormones are produced in all parts of the plant 44) Plant hormones A) must be produced in large quantities to be effective. B) act on all cells they encounter. C) are chemical signals that influence growth and development. D) are rare and produced only in response to stress. 45) Which of the following statements about plant hormones is true? A) Plant hormones are produced in small concentrations. B) Plant hormones mainly affect reproductive processes. C) Individual hormones typically have single effects. D) Plant hormones play a vital role in photosynthesis. 46) What is one main effect of auxins on plant growth? A) They reduce growth by inhibiting cell division. B) They increase growth by...
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- Fall '13